Italy is the first country to have experimented with both accruals and retrospective capital gains taxation along the lines suggested by Vickrey (1939) and Meade (1978). This paper describes the Italian experience highlighting its peculiar features and the lessons that can be learned by other countries wishing to pursue these approaches. It illustrates the mechanics of the adjustments to the realisation based capital gains tax and how far they diverge from the original proposals. The paper also draws attention to the administrative and political difficulties encountered in implementing the reform. These factors ultimately resulted in a repeal of retrospective taxation, and, in due course, may also entail the abolition of taxation on an accrual basis. The paper highlights the crucial role that financial intermediaries can play in lowering compliance costs under a proportional tax system and the effects on tax revenues.